1. Field of the Invention
The present invention relates to paperboard trays in general, and in particular to heavy duty paperboard trays with waterproof coatings and with leakproof construction so that the trays are usable as baking trays or for other food handling uses.
2. Description of the Prior Art
The prior art includes several examples of trays folded from blank material which have folded corner flaps. U.S. Pat. No. 3,927,823 discloses a food tray in which end flaps fold together and against the ends of the tray. U.S. Pat. Nos. 2,373,730 and 3,924,013 describe containers including tray parts with infolded corner extensions which are locked in place by extended portions of the end of the tray. U.S. Pat. Nos. 2,472,516 and 3,876,132 show other trays with folded corner structures. It has been a problem in prior art trays that they have generally not been sufficiently rigid and leakproof, since the corner structures have generally been either strong or leakproof but seldom both.